The invention relates to an apparatus for determining crystallization solidification curves of chocolate masses and similar fatty masses, with a measuring chamber which is formed by a cooled wall, into which projects a temperature-measuring sensor. In this measuring chamber, the liquid chocolate mass is brought to solidification, and a device records the temperature pattern in the solidifying chocolate mass in relation to time.
Before chocolate mass is processed from the liquid state and brought to solidification, it has to be heat-treated as is known; that is, it is first heated and thus brought into the liquid state and subsequently cooled, until the fatty fraction in the chocolate mass forms solidification crystals. This process is also known as precrystallization. The properties of the solidified chocolate mass differ according to the composition of the chocolate mass and the heat-treatment process used. For a good gloss, a long shelf life and fine-grained breaking of the final product, it is important that, during heat treatment, fat crystals are formed in a crystal form which is high-melting in temperature terms and that these crystal agglomerates have small dimensions and are distributed homogeneously in the chocolate mass. The degree of heat-treatment or of precrystallization, which is the fraction of solidified fat crystals, is also critical for the production flow. Too low a fraction (inadequate heat-treatment) undoubtedly causes excessively long solidification times during final cooling and can result in a poor gloss and low shelf life. Too high a solidification fraction (excessive heat-treatment) gives rise to an increased viscosity of the chocolate mass to be processed and can result in less contraction during final cooling, a poor gloss and, again, a lower shelf life.
A known apparatus of the type described in the introduction makes it possible to determine crystallization solidification curves. Sampling vessels are used, consisting essentially of a portion of copper tube, on which a small cylindrical container which represents a measuring chamber is formed in one end region. This measuring chamber is filled with liquid chocolate mass. A temperature-measuring sensor is introduced manually into the measuring chamber, that is, it is inserted into the liquid chocolate mass. The other end of the measuring sensor is connected to a recording instrument which, at intervals of time, records the particular temperature of the solidifying chocolate mass. To ensure cooling, the sampling vessel consisting of a copper tube is subjected to cooling at its lower end by being dipped into a vessel containing an ice-water mixture. As a result of the conduction of heat in the copper tube, the liquid chocolate mass in the measuring chamber is also brought to solidification, specifically in a way which can be reproduced over a period of time. A thermocouple can be used, for example, as a temperature-measuring sensor. In the device for recording the temperature pattern, a paper strip is constantly moved sideways, so that the solidification curves are recorded and thus captured. It is therefore possible, during a production operation, for the heat treatment of the chocolate mass to be processed to be checked repeatedly at intervals of time, in order to ascertain that the heat treatment is being maintained at the desired or necessary level. Correcting measures can then also be taken on the heat-treatment machine accordingly. On the one hand, the known apparatus involves a high outlay, because an attendant is needed to extract the liquid chocolate mass, introduce it into the measuring chamber and carry out the measurement. Furthermore, the measurement is also unreliable since as it is possible for the operation to take place on a completely erroneous basis. Thus, the reference temperature can even deviate from 0.degree. without being noticed. The liquid chocolate mass can experience a change between extraction at the checking point and introduction into the measuring chamber. Due to the possibility of these events, it is difficult to maintain reproducible conditions here. Moreover, the liquid chocolate mass can be extracted only at an open location on a heat-treatment machine or another processing station, and not in a closed pipeline or at other points, where access is difficult. Finally, the sampling vessels have to be cleaned again after the chocolate mass has solidified. For all these reasons, the intervals of time at which such monitoring checks are carried out are often very long.